The article deals with the parametric method of pump unit diagnostics. The well-known methods of diagnostics are described, the comparison of methods is given. The parametric method allows to determine the current state of the pumping unit on the basis of publicly available information in the process of liquid pumping. The article presents a mathematical model of the system frequency Converter, engine, pump. An example of changing the coefficients of the diagnostic model is given.

Keywords: centrifugal pumps, methods, diagnostics, parameters, mathematical model, coefficient, diagnostic models